Pressure control valve arrangement having an eccentrically mounted double magnet

ABSTRACT

A pressure control valve arrangement is described for controlling the fluid pressure in an ABS brake system of a vehicle so that, during a tendency of individual wheels of the vehicle to lock, the brake pressure in at least one assigned brake cylinder can be matched adaptively, a) two diaphragm valves and two electromagnetic control valves, activatable by an electronic control device, for the pilot control of the diaphragm valves being provided in the housing of the pressure control valve arrangement, b) the two electro-magnetic control valves having a double magnet with two magnet coils and also magnet armatures cooperating with solenoid valve seats and actuable by current being applied to the magnet coils, c) the housing having at least one pressure medium connection, connected to a service brake valve, for acting with pressure upon and/or relieving the pressure of the pressure control valve arrangement and also at least one working connection for connecting to the brake cylinder, characterized in that d) a plane of symmetry of the mid-axes of the magnet coils of the double magnet of the electromagnetic control valves is arranged parallel, and offset by the amount of an eccentricity, with respect to a mid-axis of the pressure medium connection.

FIELD OF THE INVENTION

The present invention relates to a pressure control valve arrangementfor controlling the fluid pressure in an ABS brake system of a vehicle.

BACKGROUND INFORMATION

ABS (antilock system) prevents the wheels from locking and comes intooperation when greater adhesion than is transferable is demanded betweena tire and the road, that is to say when the driver overbrakes. Inoverbraking, the central electronic control apparatus of the ABS brakesystem detects from rotational speed sensor signals the tendency of oneor more wheels to lock and from this calculates the activation of thepressure control valve arrangement acting upon the assigned brakecylinder. The brake pressure is then set to optimal slip by the pressurecontrol valve arrangement by lowering, holding or building up the brakepressure according to the wheel behavior and therefore the frictionalconditions between the tire and road.

ABS pressure control valve arrangements without a relay action, to whichthe exemplary embodiments and/or exemplary methods of the presentinvention relate, are used in vehicles, such as, for example, utilityvehicles, omnibuses, tractors and trailers. Pressure control valvearrangements without a relay action mostly have 3/2 way solenoid valvesas the pilot control valves of diaphragm valves, an electronic controldevice activating the 3/2 way solenoid valves so that the “pressureholding”, “pressure reduction” and the “pressure build-up” functionsnecessary for ABS operation can be carried out. During braking withoutthe response of the ABS (no tendency of a wheel to lock), the pressuremedium, mostly air, flows, unimpeded, through the pressure control valvearrangements in both directions when the brake cylinders are beingventilated and bled. This ensures that the functioning of the servicebrake system is not influenced by the ABS pressure control valvearrangement.

Pressure control valves of the generic type, as 1-channel pressurecontrol valves for antilock systems in motor vehicles, have in eachcase, inside the housing, a diaphragm valve as a holding valve and as anoutlet valve and also in each case an electromagnetic control valve forthe holding valve and the outlet valve. The two diaphragm valves containin each case a diaphragm capable of being acted upon by the pressure ina pilot control space, the pilot control space being closed outwardly bya cover fastened to the housing. A generic pressure control valvearrangement of an ABS brake system is known, for example, from EP 0 266555 A1 or from DE-A 2 855 876. In the pressure control valvearrangements of the prior art, the housing has a pressure mediumconnection for the action of pressure and/or the relief of pressure,which is connected to a foot-operated brake valve. Furthermore, the twodiaphragm valves are arranged laterally on the housing, thecorresponding pilot control spaces being closed by covers fastenedlaterally to the housing, that is to say, there, surface normals on thediaphragms of both diaphragm valves are arranged perpendicularly to themid-axis of the pressure medium connection.

Furthermore, in the published references, particularly according to FIG.1 of DE-A-2 855 876, a plane of symmetry of the mid-axes of the magnetcoils of the double magnet of the two electromagnetic control valves isarranged centrically with respect to a mid-axis of the pressure mediumconnection (there, the pressure medium inlet). In this case, themid-axes of the two magnet coils at the same time also define thepositions of the valve seats of the electromagnetic control valves ofthe pressure control valve arrangement, because the mid-axes of themagnet coils are arranged coaxially with the valve seats and with themagnet armatures. Furthermore, the valve seats of the electromagneticcontrol valves are connected to the pressure medium connection or issueinto this via pressure medium ducts. These pressure medium ducts may bemade coaxially with the mid-axes of the magnet coils by cuttingmanufacture, such as drilling, in order for reasons of cost to avoidhaving to rechuck the housing in order to make obliquely runningpressure medium ducts or housing bores. The pressure medium ductsconsequently run parallel to one another in a vertical direction.

So that the pressure medium ducts emanating from the valve seats of theelectromagnetic control valves can therefore be manufactured in avertical direction in the housing by cutting and at the same time bothof them can issue into the pressure medium connection, the insidediameter of the pressure medium connection has to be relatively large,especially since the magnet coils also cannot undershoot a certaindiameter. However, because a correspondingly large diameter of thepressure medium connection is unfavorable in flow terms, in practice areducing sleeve which reduces the effective flow diameter is insertedinto the pressure medium connection.

However, this procedure entails additional costs for producing andmounting the reducing sleeve, and, in view of the large number ofpressure control valve arrangements delivered by a supplier of vehicles,this amounts in total to a relatively high sum.

SUMMARY OF THE INVENTION

The subject on which the exemplary embodiments and/or exemplary methodsof the present invention are based is to develop a pressure controlvalve arrangement of the type initially mentioned in such a way that itcan be manufactured and assembled more simply and more cost-effectively.

This object may be achieved, according to the exemplary embodimentsand/or exemplary methods of the present invention, by the featuresdescribed herein.

As explained initially, the mid-axes of the magnet coils are coaxialwith the valve seats of the electromagnetic control valves, and in eachcase one valve seat is formed at one end of a pressure medium duct whichconnects the respective valve seat to the pressure medium connection.Since two electromagnetic control valves are present, two pressuremedium ducts formed in the housing must consequently lead from therespective valve seats coaxial with the mid-axes of the magnet coilsinto the pressure medium connection. In this case, pressure medium ductsrunning obliquely, that is to say deviatingly from a vertical or from ahorizontal, are to be avoided, so as to avoid having to rechuck thehousing during manufacture.

The exemplary embodiments and/or exemplary methods of the presentinvention achieve this object by providing that a plane of symmetry ofthe mid-axes of the magnet coils of the double magnet of the twoelectromagnetic control valves is arranged parallel and eccentricallywith respect to a mid-axis of the pressure medium connection.

The distance between the mouth of the connecting duct, arranged in thehousing, in the pressure medium connection between the valve seat of oneof the electromagnetic control valves and the pressure mediumconnection, on the one hand, and the mid-axis of the pressure mediumconnection, on the other hand, is then reduced, as compared with theprior art, because the mid-axis of one of the magnet coils of the doublemagnet and therefore also the valve seat, coaxial thereto, of therespective electromagnetic control valve and, too, the respectivepressure medium duct can then be moved nearer to the mid-axis of thepressure medium connection and consequently issue into the pressuremedium connection at a shorter distance from this mid-axis. The otherpressure medium duct emanating from the valve seat of the otherelectromagnetic control valve then no longer needs to run parallel tothe first, for example vertical pressure medium duct, but instead canissue, for example running in a horizontal direction, into an annularduct which is formed in a housing and which is connected in turn to thepressure medium connection. The pressure medium ducts then run in avertical and a horizontal direction, so that the housing does not haveto be rechucked during manufacture. The diameter of the pressure mediumconnection can thus be smaller and therefore more favorable in flowterms. In particular, a reducing sleeve can be dispensed with.

Advantageous developments and improvements of the exemplary embodimentsand/or exemplary methods of the present invention specified herein arepossible as a result of the measures listed in the further descriptionsherein.

Especially, the housing may be provided with at least one through borewhich issues in side faces of the housing and which is intended as aholding arrangement for holding the pressure control valve arrangementon a carrier body, the plane of symmetry of the mid-axes of the magnetcoils of the double magnet of the two electromagnetic control valvesbeing arranged, offset by the amount of the eccentricity with respect toa plane of symmetry of the through bore, said plane of symmetry beingarranged perpendicularly to a mid-axis of the through bore. As a result,the eccentric arrangement of the double magnet acquires an additionalreference to a relevant geometric quantity of the pressure control valvearrangement, because the length of the through, bore is fixed, forreasons of space, as a standardized installation dimension of thepressure control valve arrangement and is invariable. It defines themaximum width of the housing.

According to a development, in one diaphragm valve of the two diaphragmvalves, the surface normal running perpendicularly with respect to theassigned diaphragm is arranged parallel to the mid-axis of the throughbore and perpendicularly to the mid-axis of the pressure mediumconnection, and, in the other diaphragm valve, the surface normalrunning perpendicularly with respect to the assigned diaphragm isarranged perpendicularly to the mid-axis of the through bore andperpendicularly to the mid-axis of the pressure medium connection. Thismay be implemented, for example, in that one diaphragm valve is arrangedlaterally and the other diaphragm valve on the bottom side or head sideon the housing.

If a cover closing a pilot control space of one diaphragm valve, forexample arranged laterally on a housing, with respect to the outside andfastened to the housing is then composed of at least one plastic, thewall thickness of this cover can be greater than in the prior art, inwhich both diaphragm valves are arranged laterally on the housing and,because of the standardized overall width of the housing, the thicknessof the covers has to be smaller. The plastic cover which is thicker, ascompared with the prior art, is then more rigid. The tendency of thecover to deformation therefore decreases, and so the safety of therespective diaphragm valve against leakage of the pilot control space isincreased.

A cover closing a pilot control space of the other diaphragm valve withrespect to the outside and fastened to the housing may likewise becomposed of a plastic.

In this case, at least one of the covers may at the same time, with theeffect of an advantageous double function, close a pressure medium ductformed in the housing and separated from the respective pilot controlspace.

The pressure medium connection may be provided, in particular, forconnection to a service brake valve of a pressure medium-actuated brakeapparatus of a vehicle.

Further measures improving the exemplary embodiments and/or exemplarymethods of the present invention are illustrated in more detail below,together with the description of an exemplary embodiment of the presentinvention, by the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a basic illustration of an ABS brake system as a generaldiagram of a 4S/4C ABS brake system of a vehicle.

FIG. 2 a shows a diagrammatical illustration of a pressure control valvearrangement activating a brake cylinder, in the open state (pressurebuild-up).

FIG. 2 b shows a diagrammatic illustration of the pressure control valvearrangement of FIG. 2 a in the closed state (pressure reduction).

FIG. 3 shows a front view of an actual version of the pressure controlvalve arrangement of FIG. 2 a and FIG. 2 b according to an exemplaryembodiment of the present invention.

FIG. 4 shows a side view of the pressure control valve arrangement ofFIG. 3.

FIG. 5 shows a sectional illustration along the line V-V of FIG. 4.

FIG. 6 shows the other side view of the pressure control valvearrangement of FIG. 3.

FIG. 7 shows a sectional illustration along the line VII-VII of FIG. 6.

DETAILED DESCRIPTION

According to FIG. 1, a vehicle equipped with an ABS brake system has afront axle 1 and a rear axle 2. Wheels 3 a and 3 b are arranged on thefront axle 1; the rear axle 2 has, for example, wheels 4 a and 4 b ineach case equipped with twin tires. The ABS brake system serving forbraking these wheels 3 a, 3 b and 4 a, 4 b is designed here in themanner of a 4S/4C system (four sensors, four channels). This means that,overall, four rotational speed sensors 5 a-5 d and four pressure controlvalve arrangements 7 a-7 d are available here. The pressure controlvalve arrangements 7 a-7 d serve for the activation of respectivelyassigned brake cylinders 6 a-6 d. All the pressure control valvearrangements 7 a-7 d are connected to a foot-operated brake valve 9 viaa branching pneumatic brake pressure line 8.

The driver, when actuating the foot-operated brake valve 9, generates abrake pressure which, passing through the pressure control valvearrangements 7 a-7 d, is transferred by the pneumatic brake pressureline 8 to the brake cylinders 6 a-6 d assigned to the wheels 3 a, 3 band to the wheels 4 a, 4 b.

The pressure control valve arrangements 7 a-7 d are activatable viaintegrated electromagnetic valves 15 a, 15 b shown in FIG. 2 a, FIG. 2 band FIG. 4 and for this purpose are connected electrically to a centralelectronic control unit 10. The electronic control unit 10 is connectedon the input side to the four rotational speed sensors 5 a-5 bdetermining the wheel speeds. In the event of the locking of a wheel 3a-3 d, the brake pressure selected by the driver via the foot-operatedbrake valve 9 is lowered correspondingly to an ABS control, according tothe electronic control unit 10, by the corresponding pressure controlvalve arrangements 7 a-7 d until locking is eliminated. The ABS brakesystem of the present exemplary embodiment comprises, furthermore, anASR function which comprises an ASR unit 11 for reducing the enginetorque, such as an ASR solenoid valve 12 and a shuttle valve 13.

The pressure control valve arrangement 7 used according to FIG. 2 awithin the framework of the ABS brake system for the purpose of ABScontrol is constructed here in the manner of a 1-channel pressurecontrol valve arrangement and is composed essentially of two integrateddiaphragm valves 14 a and 14 b and of two spring-loaded electromagneticvalves 15 a, 15 b activating these. The diaphragm valves 14 a and 14 bare in each case loaded in the closing direction by spring elements 16a, 16 b and are pilot-controlled via the respectively assignedelectromagnetic valves 15 a and 15 b.

A pressure control valve arrangement 7 is shown in FIG. 2 a in its openposition, in which a build-up of pressure to the connected brakecylinder 6 takes place. In this case, neither of the solenoid valves 15a and 15 b is activated electrically. In the position shown, thecompressed air coming from the foot-operated brake valve 9 presses ontothe diaphragm valve 14 a designed as an inlet valve. The normally closedelectromagnetic valve 15 a prevents the assigned diaphragm valve 14 afrom being closed again. By the normally open second electromagneticvalve 15 b, the brake pressure coming from the foot-operated brake valve9 closes the second diaphragm valve 14 b serving as an outlet valve. Thecompressed air thus runs, unimpeded, through the pressure control valvearrangement 7. The pressure control valve arrangement 7 is in this stateeven when ABS control does not take place.

To keep the brake pressure constant in a brake cylinder 6 a to 6 d,current merely has to be applied to the electromagnetic valve 15 a, withthe result that this opens and consequently the brake pressure comingfrom the foot-operated brake valves 9 presses the inlet-side diaphragmvalve 14 a shut. The pressure on the right and the left side of thediaphragm valve 14 a is then equal. However, since the active surface onthe left side of the diaphragm valve 14 a is greater, the diaphragmvalve 14 a is closed. The same applies correspondingly to theoutlet-side diaphragm valve 14 b activated via the electromagnetic valve15 b. To keep the pressure constant, therefore, the pressure controlvalve arrangement 7 closes the pneumatic brake pressure line 8 runningfrom the foot-operated brake valve 9 to the brake cylinder 6.

According to FIG. 2 b, a pressure reduction in a brake cylinder 6 a to 6d is achieved in that current is applied to both electromagnetic valves15 a and 15 b. What was described above for holding the pressure appliesto the electromagnetic valve 15 a and the assigned inlet-side diaphragmvalve 15 a. By contrast, the other electromagnetic valve 15 b, by havingcurrent applied to it, is closed. The pressure coming from the brakecylinder 6 therefore presses the outlet-side diaphragm valve 14 b openand the brake cylinder 6 is bled.

The above-described functions of the pressure control valve arrangement7 are carried out according to the electronic control unit 10, withinthe framework of ABS/ASR control, in the way described initially.

FIG. 3 to FIG. 5 show the pressure control valve arrangement 7illustrated merely diagrammatically in FIG. 2 a and FIG. 2 b in anactual embodiment in the installation position, that is to say thecomponents illustrated at the top are located at the top. In thisembodiment, the two electromagnetic valves 15 a, 15 b for the pilotcontrol of the diaphragm valves 14 a, 14 b are combined in a doublesolenoid valve, the function of which, however, is analogous to that ofthe individual valves 15 a, 15 b.

The two electromagnetic valves 15 a, 15 b have a double magnet 18combined in a block 17 and having two magnet coils 19 a, 19 b whichcooperate with two solenoid valves seats 20 a, 20 b. As may be gatheredclearly from FIG. 5, magnet armatures 36 a, 36 b cooperating with thesolenoid valves seats 20 a, 20 b of the electromagnetic valves 15 a, 15b are actuated as valve closing members by current being applied to themagnet coils 19 a, 19 b.

The block 17 comprising the double magnet 18 is fastened, which may beon the front side, to a housing 21 of the pressure control valvearrangement 7 and has a plug connection 22 for supplying current to thedouble magnet 18. This housing 21 has, furthermore, a pressure mediumconnection 23 for the action of pressure upon and/or the relief ofpressure of the pressure control valve arrangement 7, and also a workingconnection 24, as can be seen in FIG. 4, for connecting the brakecylinder 6.

As shown in FIG. 2 a and FIG. 2 b, the pressure medium connection 23 isconnected via the brake pressure line 8 to the foot-operated or servicebrake valve 9 of the pressure medium-actuated brake apparatus and isventilated or bled according to actuation of the foot-operated brakevalve 9.

As many be gathered particularly from FIG. 5, the mid-axes 25 a, 25 b ofthe magnet coils 19 a, 19 b are coaxial with the solenoid valve seats 20a, 20 b of the electromagnetic valves 15 a, 15 b, and in each case onesolenoid valve seat 20 a, 20 b is formed at one end of a pressure mediumduct 26 a, 26 b which connects the respective solenoid valve seat 20 a,20 b to the pressure medium connection 23.

A plane of symmetry 27, shown in FIG. 3, of the mid-axes 25 a, 25 b ofthe magnet coils 19 a, 19 b of the double magnet 18 of the twoelectromagnetic valves 15 a, 15 b is arranged, offset eccentrically bythe amount of an eccentricity e with respect to a mid-axis 28 of thepressure medium connection 23. The mid-axis 28 of the pressure mediumconnection 23 is parallel with respect to this plane of symmetry 27.

The distance between the mouth of, for example, the pressure medium duct26 in the pressure medium connection 23 and the mid-axis 28 of thepressure medium connection 23 is then reduced, because the mid-axis 25 aof one of the magnet coils 19 a of the double magnet 18 and consequentlyalso the solenoid valve seat 20 a of the respective electromagneticvalve 15 a and also the respective pressure medium duct 26 a are thenmoved nearer to the mid-axis 28 of the pressure medium connection 23,and consequently the pressure medium duct 26 a can then issue into thepressure medium connection 23 at a shorter distance from said mid-axis,as shown clearly in FIG. 5. Of course, the double magnet 18 may also bearranged, offset by the amount of an eccentricity e, in the otherdirection, in FIG. 3 to the right with respect to the mid-axis 28 of thepressure medium connection 23.

According to the eccentricity e, however, the distance of the otherpressure medium duct 26 b emanating from the solenoid valve seat 20 b ofthe other electromagnetic valve 15 b from the mid-axis 28 of thepressure medium connection 23 is increased. This pressure medium duct 26b therefore does not issue directly into the pressure medium connection23, but instead first, for example, into an annular duct 29 which isformed in the housing 21 and which is connected, in turn, to thepressure medium connection 23. The eccentricity may amount to more than1 mm.

The housing 21 is provided with at least one, here, for example, two,through bores 31 a, 31 b which issue into the two side faces 30 a, 30 bof the housing 21 and through which a project holding arrangement, forexample screws, for holding the pressure control valve arrangement on acarrier body, for example on a chassis of the vehicle. The mid-axes 32a, 32 b of the two through bores 31 a, 31 b may be parallel to oneanother.

In this case, the plane of symmetry 27 of the mid-axes 25 a, 25 b of themagnet coils 19 a, 19 b of the double magnet 18 of the twoelectromagnetic valves 15 a, 15 b is arranged eccentrically with respectto a plane of symmetry 33 arranged perpendicularly to the mid-axes 32 a,32 b of the through bores 31 a, 31 b, as may be gathered from FIG. 3. Inthis case, the mid-axis 28 of the pressure medium connection 23 lies inthis plane of symmetry. The axial length of the through bores 31 a, 31 bis deemed a standardized installation dimension of the pressure controlvalve arrangement 7 and, for reasons of space, is fixed and invariable,and it defines the maximum permissible width B of the housing 21.

One diaphragm valve 14 a may be arranged laterally and the otherdiaphragm valve 14 b may be arranged on the bottom side on the housing21, as shown in FIG. 4 and FIG. 7.

Such a diaphragm valve 14 a, 14 b has, as a valve body, a diaphragm 34a, 34 b which can be acted upon by pressure medium being introduced intoa control chamber 38 a, 38 b which is covered in each case on thehousing outside by a cover 35 a, 35 b which is produced by primaryforming, such as injection molding, and which is fastened to the housing21. In this case, the control chamber 38 a, 38 b is formed between thediaphragm 34 a, 34 b and the cover 35 a, 35 b. The covers 35 a, 35 b maybe composed of at least one plastic.

At least one of the covers 35 a, 35 b may be designed such that, inaddition to its function as a closing body for the assigned controlchamber 38 a, 38 b, it at the same time closes a bore which is formed inthe housing 21 and is not intended for connection to the control chamber38 a, 38 b and which issues into a side face 30 a, 30 b of the housing21.

With regard to one diaphragm valve 14 a of the two diaphragm valves 14a, 14 b, the surface normal running perpendicularly with respect to theassigned diaphragm 34 a may be parallel to the mid-axes 32 a, 32 b ofthe through bores 31 a, 31 b and perpendicular to the mid-axis 28 of thepressure medium connection 23, as can easily be imagined from FIG. 3. Asregards the other diaphragm valve 14 b, by contrast, the surface normalrunning perpendicularly with respect to the assigned diaphragm 34 b isarranged perpendicularly to the mid-axes 32 a, 32 b of the through bores31 a, 31 b and perpendicularly to the mid-axis 28 of the pressure mediumconnection 23. In other words, in the view of FIG. 3, one diaphragmvalve 14 a is then arranged laterally and the other diaphragm valve 14 bon the bottom side or, alternatively, on the head side on the housing21.

THE LIST OF REFERENCE SYMBOLS IS AS FOLLOWS

1 Front axle

2 Rear axle

3 Wheel

4 Wheel

5 Rotational speed sensor

6 Brake cylinder

7 Pressure control valve arrangement

8 Brake pressure line

9 Foot-operated brake valve

10 Control unit

11 ASR unit

12 ASR solenoid valve

13 Shuttle valve

14 a/b Diaphragm valve

15 a/b Electromagnetic valve

16 a/b Spring element

17 Block

18 Double magnet

19 a/b Magnet coils

20 a/b Solenoid valve seats

21 Housing

22 Plug connection

23 Pressure medium connection

24 Working connection

25 a/b Mid-axes magnet coils

26 a/b Pressure medium duct

27 Plane of symmetry

28 Mid-axis

29 Annular duct

30 a/b Side faces

31 a/b Through bores

32 a/b Mid-axes

33 Plane of symmetry

34 a/b Diaphragm

35 a/b Cover

36 a/b Magnet armature

38 a/b Control chamber

1-8. (canceled)
 9. A pressure control valve arrangement for controllinga fluid pressure in an ABS brake system of a vehicle so that, during atendency of individual wheels of the vehicle to lock, a brake pressurein at least one assigned brake cylinder can be matched adaptively,comprising: two diaphragm valves and two electromagnetic control valves,activatable by an electronic control device, for a pilot control of thediaphragm valves being provided in a housing of the pressure controlvalve arrangement, the two electromagnetic control valves having adouble magnet with two magnet coils and also magnet armaturescooperating with solenoid valve seats and actuable by current beingapplied to the magnet coils, the housing having at least one pressuremedium connection, connected to a service brake valve, for acting atleast one of with pressure upon and relieving the pressure of thepressure control valve arrangement and also at least one workingconnection for connecting to the brake cylinder; wherein a plane ofsymmetry of the mid-axes of the magnet coils of the double magnet of theelectromagnetic control valves is arranged parallel, and offset by theamount of an eccentricity, with respect to a mid-axis of the pressuremedium connection.
 10. The pressure control valve arrangement of claim9, wherein the housing includes at least one through bore which issuesin side faces of the housing and which is configured as a holdingarrangement for holding the pressure control valve arrangement on acarrier body, the plane of symmetry of the mid-axes of the magnet coilsof the double magnet of the two electromagnetic control valves beingarranged, offset by the amount of the eccentricity with respect to aplane of symmetry of the through bore, the plane of symmetry beingarranged perpendicularly to a mid-axis of the through bore.
 11. Thepressure control valve arrangement of claim 10, wherein in one diaphragmvalve of the diaphragm valves, the surface normal runningperpendicularly with respect to the assigned diaphragm is arrangedparallel to the mid-axis of the through bore and perpendicularly to themid-axis of the pressure medium connection, and, in the other diaphragmvalve, the surface normal running perpendicularly with respect to theassigned diaphragm is arranged perpendicularly to the mid-axis of thethrough bore and perpendicularly to the mid-axis of the pressure mediumconnection.
 12. The pressure control valve arrangement of claim 11,wherein a cover closing a pilot control space of one diaphragm valvewith respect to the outside and fastened to the housing is composed ofat least one plastic.
 13. The pressure control valve arrangement ofclaim 11, wherein a cover closing a pilot control space of the otherdiaphragm valve with respect to the outside and fastened to the housingis composed of at least one plastic.
 14. The pressure control valvearrangement of claim 12, wherein at least one of the covers at the sametime closes a pressure medium duct formed in the housing and separatedfrom the respective pilot control space.
 15. The pressure control valvearrangement of claim 9, wherein the pressure medium connection isprovided for connection to a service or foot-operated brake valve of apressure medium-actuated brake apparatus of a vehicle.
 16. Atraction-controlled and pressure medium-actuated brake apparatus of avehicle, comprising: at least one pressure control valve arrangement forcontrolling a fluid pressure in an ABS brake system of a vehicle sothat, during a tendency of individual wheels of the vehicle to lock, abrake pressure in at least one assigned brake cylinder can be matchedadaptively, including: two diaphragm valves and two electromagneticcontrol valves, activatable by an electronic control device, for a pilotcontrol of the diaphragm valves being provided in a housing of thepressure control valve arrangement, the two electromagnetic controlvalves having a double magnet with two magnet coils and also magnetarmatures cooperating with solenoid valve seats and actuable by currentbeing applied to the magnet coils, the housing having at least onepressure medium connection, connected to a service brake valve, foracting at least one of with pressure upon and relieving the pressure ofthe pressure control valve arrangement and also at least one workingconnection for connecting to the brake cylinder; wherein a plane ofsymmetry of the mid-axes of the magnet coils of the double magnet of theelectromagnetic control valves is arranged parallel, and offset by theamount of an eccentricity, with respect to a mid-axis of the pressuremedium connection.